Polarization percentage of the debiased weighted polarization intensity map against the Commander synchrotron total intensity fit evaluated at 22.8 GHz. Uncertainties in the component separation discussed in the text, and also uncertainty in the absolute zero level, make this highly uncertain, except in regions of strong synchrotron emission, such as the North Polar spur and the inner Galactic halo (see also discussion in Vidal et al. 2015).